Marty Cagan in his book “Inspired” defines a Customer Misbehavior as the act of using “[…] our products to solve problems other than what we planned for and officially support”
Do you encourage them or you get upset when your product starts to be used for unintended use cases? Is this an opportunity or something to fix?
If it doesn’t interfere with my main customers or cause anyone problems or harm, and it doesn’t break any laws, they are welcome to go for it. If it’s a physical product, it’s their property once they buy it. They can disassemble it, modify it, fix it, resell it, give it away, destroy it, and otherwise use it in unintended ways all they want.
If it’s a digital product, there are IP laws that disallow piracy and unauthorized commercial use and stuff like that, but I don’t really care about how people use my digital products if it’s just for personal use (again, assuming they are not harming anyone). If they want to print posters of it, use it as art references, hold viewing parties, or whatever else, it’s fine by me.